Here's why:
* Characters, storylines, and settings are protected: The Horcruxes are a specific element of the Harry Potter story, including their names, descriptions, and properties. As part of the overall fictional world, they are copyrighted.
* Copyright applies to creative works: Copyright protects original works of authorship, including literary, dramatic, musical, and certain other intellectual works.
* J.K. Rowling owns the rights: J.K. Rowling is the author of the Harry Potter series, and she holds the copyright to its elements, including the Horcruxes.
Therefore, using the Horcruxes in a way that could be considered infringing on copyright, such as creating a commercial product or writing a story that heavily relies on them, would likely require permission from J.K. Rowling or her publishers.
It's important to note that fair use can apply in some cases, allowing for limited use of copyrighted material for purposes like criticism, commentary, or parody. However, even with fair use, it's always best to be mindful of the original work's copyright and avoid excessive reliance on its elements.